Drive gear for sewing machines



Aug. 11, 1931. R. s. KELSO 1,818,336

DRIVE GEAR FOR SEWING MACHINES Filed Nov. 29, 1929 2 sheets sheet l Jwoemfer @6 (use Wre -M Aug. 11, 1931. R. s' KELSO DRIVE GEAR FOR SEWING MACHINES Filed Nov. 29, 1929 2 Sheets-Sheet 2 Patented Aug. 11, 1931 UNITED STATES PATENT QFFICE RALPH S.

nnso, or nooxronn, ILLINOIS, ass enoa TO THE FREE snwrNG aonrnn COMPANY, or ROCKFORD, ILLINOIS, A CORPORATION OF ILLI voIs DRIVE GEAR FOR SEWING MACHINES Application filed November 29, 1929. Serial K0. 410,562.

This invention relates to sewing machines,

and more'particularly to novel motor driving I means fora sewing machine.

It is the common practice to provide sewing machines with drive motors pivotally connected to the heads of the machines and having resilient driving pulleys carried by the armature shafts thereof and frictionally engaging the hand wheel of the machine. Such constructions involve several disadvantages." For example, rather large and cumbersome hand wheels are employed, and since such wheels have curved outer surfaces, they soon cause the rubber or other resilient driving pulleys of the motor to become deformed.

An important object of the present invention is to provide a novel form of drive means for sewing machines wherein a resilient driving pulley is employed, but wherein the deforming of the pulley is prevented over long periods of operation.

A further object is to provide a device of the. character referred to wherein'the resilient driving pulley constitutes an intermediate driving element between the motor shaft and hand wheel thus permitting thelatter to be made much smaller and lighter than is the common practice. A further object is to provide novel means for encasing the driving elements of the ma chine and for connecting the casing elements to the machine.

A further object is to provide novellubricatingmeans for the shaft of the resilient driving wheel.

.A further object is to provide a single fastening element for connecting the two sectionsof the transmission casing to each other and to the machine, and for supporting the resilient driving wheel.

Other objects and advantages of the invention will become apparent during the course ofthe following description.

In the drawings I have shownone embodim'ent of the invention. In this showing,

Figure 1 is a rear elevation of the sewing machine showing the invention applied,

Figure 2 is an end elevation of the same,

Figure 3 is" a section on line 3-3 of Figure 3 1,parts being shown injele'vation,

sewin opening 19.

parent,

Figure 41 is an enlarged fragmentary end elevation of the machine, parts being shown in'se ction,

Figure 5 is a detail perspective view of the resilient driving element and associated parts, and, I

Figure 6 is a detail section on line 66 of Figure 2.

Referring to the drawings the numeral 10 designates a sewing machine as a whole including a bed 11, and a head including a standard 12 and horizontal arm 13. The

g machine, aside from the driving means to be described, operates in the usual manner and forms no part of the present invention. the operating shaft 14 extending through the arm 13'is provided at oneend with a hand wheel 15 of substantially smaller diameter than ordinary constructions.

A motor 16 is arranged at the rear of the head of the machine and includes a pair of easing sections'17 secured together in any' 21 is carried by the inner face of the motor casing and has its ends engaging the inner face of the rear wall of the head to retain the motor in operative position. It will be apparent that the motor is pivoted to swing As shown in Figures 1, '2 and 4,

about the horizontal axisof the spherical The motor is provided with an armature shaft 22 to the outer end of which is secured apreferably metallic driving wheel or disk 23. As will become apparent, it is desirable to have the disk 23 normally urged upwardly, and for this reason, a spring 24; is connected at itsupper end to the motor casing, within the head of the machine, to normally effect turning movement of the motor to swing the disk 23 upwardly. A screw 25 is connected to the lower end of the spring and is adapted to adjust the tension th.ereof,'aswill be ap- A resilient driving wheel 26 is interposed between the disk -3 and the hand wheel 15, as clear y shown in Figure 4, and it will be apparent that the axis of the *heel 26 is below a line drawn between the axes of the wheels 15 and 23. As vill become apparent, this construction assures firm engagement between the wheel 26 and the peripheries of the wheels 15 and 23 to f0 m an ellicient driving connection.

The wheel 26 is provided with a concentric central bushing 27 preferably formed of bronze or other bearing metal,- and is rotatable upon a shaft 28. as shown in Figure 6. The shaft 28 is hollo as indicated at 29. and radial openings 30 communicate between the 29 and the interior of the sleeve 27 A wick Bl has one end extending into the opening to supply lubricant to this ing and thus to the interior of the huiriii 27 through the openings 8).

One end of ti shaft 28 is enlarged treat 32 to forn'i a collar adapted to retain the bushing 2? on the shaft, while the opposite end of this shaft i reduced and riveted or otherwise secured as at 33 to one end of an arm 34. The opposite end of the arm 34 is provided with a sleeve 35 arranged parallel to the axis of the shaft 28 and having an open ing therethrough for a purpose to be described.

lhe w heels 23 and 26 constitute the transawn in Figure l, the inner end of the seats against the inner wall of a reces: ll formed in the outer motor casing section 11'. These casing sections are provided with alineil openings 42, and the inner open ng 's internally threaded to receive the inner threaded end of a screw 43. This provided with a head all eounteri t-e outer casing section 37, and the ejects through the boss 40, as shown he 1. it. will be apparent that the screw ll} ser es to connect the two casing section :37 a

Y nd 38 to each other and to the motor 16. Referring" to Figure l, it will be noted that the portion of the screw 43 lying within the casing 36 passes througlr the sleeve and accordingly pivotally supports the arm 3 Since the casing 36 is carried by the motor 16, it obviousl moves therewith about the axis of the spherical opening 19.

Referring to Figure 6, the numeral 45 designat'es an integral boss carried by the outer face of the casing section 37 and provided with an opening therethrough receiving a wick 46 extending within the transmission casing and contacting with the outer end of the wick 31.

The operation of the device is as follows:

it will be apparent tl at the spring 2i oper ates to swing the motor about the axis of the spherical opening 19, and hus the driving disk 23 of thc motor shaft will be constantly urged upwardly. This action maintains the disk 28 in snug contact with the resilient driving member 26, and also retains the latter element in firm engagement with the periphery of the hand wheel 15. The wheel 26 is carried by the pivoted arm 84, and accordingly the wheel :26 is adapted to alter its position whereby it firmly engages the wheels 15 and 28 with uniform pressure. The arrange ment of the axis of the wheel 26 below a line joining the axes of the wheels 15 and 23 operates in such a manner that the tendency of the wheel 23 to move upwardly under the influence of the spring 24: urges the wheel 26 more ti htly into engagement with the wheels 10 and 23, thus increasing the elliciency of the driving connection.

In standard sewing machine driving constructions, it is the common practice to place a resilient driving wheel directly on the 1notor shaft to contact with and drive the hand wheel of the machine. Obviously such arrangement requires the use of a relatively heavy and cumbersome driving wheel 15 whereas in the present construction the use of an intermediate resilient driving wheel between the motor shaft and the hand wheel permits the use of a hand wheel of materially lighter construction and smaller diameter.

The hand wheels of all sewing machines are formed with convex peripheries and with the standard constructions, the curved outer periphery of the hand wheel constantly contacts with the resilient driving wheel on the motor shaft with the result that such driving wheel becomes deformed and tends to lose its driving efficiency. lVith the present construction, the curved periphery of the hand wheel tends to depress the peripheral portion of the wheel 26 to deform the resilient material of which this wheel is formed, but this tendency is overcome by virtue of the fact that the wheel bears under uniform pressure against the wheels 15 and 23, and the outer face of the latter wheel is transversely flat thus preventing the deforming of the wheel 26. Thus the traction between the friction driving elements remains constant and eiiicient over long periods of time.

The resilient driving wheel is properly lubricated merely by occasionally oiling the upper end of the wick 46. The lubricant will be carried by capillary attraction downward- 1y through the wick 46 to the wick 31, from lav which it is delivered in small quantities to the interior of the bushing 27 through the openings 29 and 30. Thus it will be apparent that proper lubrication readily may be provided for the resilient driving wheel, while the shafts 14 and 22 can be lubricated by the usual means provided for such purpose.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the su] joined claims.

I claim:

1. T he combination with a sewing machine including a rotatable element having a transversely curved peripheral surface, of a motor having a drive shaft, a cylindrical driving member mounted on said shaft, a substantially cylindrical resilient frictional driving connection arranged between and contacting with said driving member and said rotatable element, and resilient means normally urging said driving member toward said driving connection and said rotatable element.

2. The combination vith a sewing machine including a rotatable element, of a motor having drive sh aft, a driving member mounted on said shaft, means for pivotaily connecting said motor to a stationary portion of the sewing machine whereby said driving member is adapted to swing toward and away from said rotatable element, spring means tending to revolve said motor whereby said driving member is urged toward said rotatable element, a resilient frictional driving connection arranged between and contacting with said driving member and said rotatable element, an arm pivotally supported at one end by the motor, and a shaft carried by the free end of said arm and rotatably supporting said driving connection.

3. The combination with a sewing machine ii'iclnding a rotatable element having a transversely curved peripheral surface, of a motor having a drive shaft, a cylindrical driving member mounted on said shaft, a substantially cylindrical resilient frictional driving connection arranged betweenandcontacting with said driving member and said rotatable element, means for pivotally connecting said motor to a stationary portion of a sewing machine whereby said driving member is adapted to swing toward and away from said rotatable element, spring means tending to urge said driving member toward said driving connection and said rotatable element, and floating means for rotatably supporting said driving connection to permit it to automatically engage under uniform pressures against said driving member and said rotatable element.

4:. The combination with a sewing machine .tion engaging said driving 7 shaft, a resil ent 'fTlLoK i tunrengaged by said dri including a rotatable element, .ofa motor having: fl ClTlVG shaft, a driving member mounted on saidshaft, means for pivotally connecting said motorsto a stationary portion of the sewing machine. whereby said driving memberis adapted'to swing toward and away from said rotatable element, spring means tending to revolve said motor. whereby said driving member isurged toward said rotatable element, a resilient frictional driving connection arrangedbetween and contacting with said driving member'a'nd said rotatable element,

said. driving connection'being arranged to one side of the plane passing through the axes ofsaiddriving member and said rotatable element, a pivot pin carried by said. motor, an arm pivotally supported at one end by said pix-*otspin,= and a shaft carried by the free end of said-arm and rotatably supporting said driving connection.

The combination with a sewing machine including a rotatable element, of a motor includinga casing and a drive shaft, a driving member moun ed on said shaft, a resilient frictional driving connection arranged be tween. and contactingwith said driving memberand said rotatable element, a casing surrounding said driving member and said driving connection and includin a pair of sections,- an arm having means at one end thereof for rotatably supporting said driving connection, and common means for securing said casing sections to each other and to the easingof the motor and for pivotally supporting the other end of said arm.

6. A device of the-character described comn-ising a motor including a casing and a drive shaft, a driving member carried by said shaft, a resilient frictiona drivmg connec' i ember, means for supporti said motor qh respect to a sewing machine whereby said driving connection will have frictional-engagement with the hand wheel of the machine, and floating means carried by said casing for rotatably supportingsaid orivmg connection to permit it'to automatically engage under uniform said motor, and means connected at the free I end of said arm for rotatably supporting said driving connection.

8. A device of the character described comprising a motor including a casing and a drive shaft a dIIVHl member carried b said shaft, a resilient frictional driving connection engaged by said driving member, means for supporting said motor with respect to a sewing machine whereby said driving con- 3 nection will have frictional engagement with the hand wheel of the machine, an arm having means at one end for rotatably supporting said driving connection, a casing for said driving member and said driving connection and including a pair of sections, and common means for securing said casing sections to each other and to the casing of the motor and for pivotally supporting the other end of said arm.

9. A device of the character described comprising a motor including a casing and a drive shaft, a driving member carried by said shaft, a frictional driving connection engaging said member, means for supporting said motor with respect to a sewing machine whereby said driving connection will have frictional engagement with the hand wheel of the machine, a casing covering said driving member and said driving connection, and common means for securing said second named casing to said motor casing and for supporting said driving connection for floating movement to permit it to automatically engage under uniform pressures against said driving member and the hand wheel of the machine.

10. A device of the character described comprising a motor including a casing and a drive shaft, a driving member carried by said shaft, a frictional driving connection engaging said member, means for supporting said motor with respect to a sewing machine whereby said driving connection will have frictional engagement with the hand wheel of the machine, a casing covering said driving member and said driving connection, an arm having means including a shaft arranged at one end thereof for rotatably supporting said driving connection, said last named shaft having an axial opening extending thereinto from one end and being further provided with radial openings communicating with said axial opening, capillary means arranged in the openings of said last named shaft, means carried by said casing for supplying lubricant to said capillary means, and common means for securing said second named casing to the casing of said motor and for rotatably supporting the other end of said arm.

In testimony whereof I affix my signature.

RALPH S. KELSO. 

